THE WINGSPREAD STATEMENT--PART 1: CHEMICALS IN
ENVIRONMENT AFFECT SEXUAL DEVELOPMENT IN WILDLIFE.
AND HUMANS?

Gradually during recent years a new body of knowledge has
developed showing that some chemicals in food and water can mimic
hormones and disrupt the development of living things like fish,
birds, and mammals, including their sexual development.

In some cases, the effects on wildlife have been dramatic. For
example, male herring gulls on Lake Ontario, exposed to DDT and
other organochlorine compounds, developed female sex organs.
Female-female pairing has been observed in herring gulls on Lake
Michigan and on Santa Barbara Island, California. Because humans
share the same basic mechanisms of growth and development as
wildlife, an increasing number of scientists has become concerned
that humans may already be affected without recognizing it.

In July of this year an international group of 21 scientists met
at Wingspread in Racine, Wisconsin to assess what is known about
these matters. They have now released a "consensus statement"
containing information and opinions about the nature and possible
causes of these problems. The five-page statement is called
"Chemically Induced Alterations in Sexual Development: The
Wildlife/Human Connection."

Background

Hormones are produced by the endocrine system--a bodily system
consisting of specialized cells, tissues, and organs that create
and secrete (usually into the blood) organic chemicals called
hormones, which then regulate other kinds of cells in the body.
Particular hormones only affect particular cells that contain
"receptors" for those hormones. A small amount of a hormone
attaches to a "receptor site" and the hormone-receptor pair then
initiates a cascade of chemical changes, often with major and
far-reaching consequences.

The endocrine system shares with the nervous system the job of
adjusting the body's response to a changing external environment.
The nervous system copes with environmental changes on an
immediate basis, whereas the endocrine system copes with
environmental changes on a sustaining basis. For example, when
the body gets cold, the nervous system causes shivering, which
raises the body's temperature. But each month it is the endocrine
system that starts the human female menstrual cycle. In a
developing fetus, it is the endocrine system that regulates cell
division and organ differentiation. The endocrine system
regulates pattern and timing of bird migration and of hibernation
in mammals. Examples of endocrine glands in humans include the
adrenal gland, pancreas, thyroid, pituitary, ovaries and testes.

The scientists gathered at Wingspread last July focused on the
sex hormones--the androgens that make males look and act like
males and the estrogens that make females look and act like
females. The Wingspread Statement begins, "Many compounds
introduced into the environment by human activity are capable of
disrupting the endocrine system of animals, including fish,
wildlife, and humans. The consequences of such disruption can be
profound because of the crucial role hormones play in controlling
development...."

"The following consensus was reached by participants at the
workshop. "[1]. We are certain of the following:

"A large number of man-made chemicals that have been released
into the environment, as well as a few natural ones, have the
potential to disrupt the endocrine system of animals, including
humans. Among these are the persistent, bioaccumulative,
organohalogen compounds that include some pesticides (fungicides,
herbicides, and insecticides) and industrial chemicals, other
synthetic products, and some metals.[1]

"Many wildlife populations are already affected by these
compounds. The impacts include thyroid dysfunction [impaired or
abnormal functioning] in birds and fish; decreased fertility in
birds, fish, shellfish, and mammals; decreased hatching success
in birds, fish and turtles; gross birth deformities in birds,
fish and turtles; metabolic abnormalities [impaired or abnormal
use of energy, manufacture of tissue, or handling of resulting
wastes] in birds, fish, and mammals; behavioral abnormalities in
birds; demasculinization and feminization in male fish, birds,
and mammals; defeminization and masculinization of female fish
and birds; and compromised [impaired] immune systems in birds and
mammals.

"The patterns of effects vary among species and among compounds.
Four general points can nonetheless be made: (1) the chemicals of
concern may have entirely different effects on the embryo, fetus,
or perinatal [meaning "near the time of birth," from the 28th
week of pregnancy through the first week of life, in humans]
organism than on the adult; (2) the effects are most often
manifested in offspring, not in the exposed parent; (3) the
timing of exposure in the developing organism is crucial in
determining its character and future potential; and (4) although
critical exposure occurs during embryonic development [from
conception through the end of the second month of pregnancy],
obvious manifestations [effects] may not occur until maturity.

"Laboratory studies corroborate the abnormal sexual development
observed in the field and provide biological mechanisms to
explain the observations in wildlife.

"Humans have been affected by compounds of this nature, too. The
effects of DES (diethylstilbesterol), a synthetic therapeutic
agent, like many of the compounds mentioned [in footnote 1] are
estrogenic [meaning they act like estrogen, a family of female
sex hormones]. Daughters born to mothers who took DES now suffer
increased rates of clear cell adenocarcinoma [cancer], various
genital tract abnormalities, abnormal pregnancies, and some
changes in immune responses. Both sons and daughters exposed in
utero [while in the uterus] experience congenital anomalies of
their reproductive system and reduced fertility. The effects seen
in in utero DES-exposed humans parallel those found in
contaminated wildlife and laboratory animals, suggesting that
humans may be at risk to those same environmental hazards as
wildlife."

"Some of the developmental impairments reported in humans today
are seen in adult offspring of parents exposed to synthetic
hormone disruptors (agonists and antagonists) released in the
environment. The concentrations of a number of synthetic hormone
agonists and antagonists measured in the U.S. human population
today are well within the range and dosages at which effects are
seen in wildlife populations. [An agonist is a chemical that is
not a hormone but mimics a natural hormone; an antagonist
interferes with a natural hormone.] In fact, experimental results
[in animals] are being seen at the low end of current
environmental concentrations [in humans].

"Unless the environmental load of synthetic hormone disruptors is
abated and controlled, large scale dysfunction at the population
level is possible. The scope and potential hazard to wildlife and
humans are great because of the probability of repeated and/or
constant exposure to numerous synthetic chemicals that are known
to be endocrine disruptors...."[3]. Current models predict that:

"... Both exogenous (external source) and endo-genous (internal
source) androgens (male hormones) and estrogens (female hormones)
can alter the development of brain function.

"Any perturbation [disturbance] of the endocrine system of a
developing organism may alter the development of that organism:
typically these effects are irreversible. For example, many
sex-related characteristics are determined hormonally during a
window of time in the early stages of development, and can be
influenced by small changes in hormone balance. Evidence suggests
that sex-related characteristics, once imprinted, may be
irreversible."

The Wingspread statement then gives three reasons why these
predictions are subject to "many uncertainties:" (1) effects of
exposure of humans are not well understood, especially exposure
of embryos; (2) data on reproductive problems in wildlife exist
but data on behavior changes are not so readily available; (3)
the potency of many synthetic [human-created] estrogenic
chemicals is not well known.

The British publisher, Elsevier Applied Science, will publish a
book on this subject by next fall. Until then, the best source of
information is Theodora E. Colborn and others, GREAT LAKES GREAT
LEGACY? available for $20.00 (plus $2.00 shipping) from: World
Wildlife Fund, P.O. Box 4866, Hampden Post Office, Baltimore, MD
21211; phone (301) 516-6951.

For $3.00 plus stamped, self-addressed envelope, we can send you
the Wingspread statement itself.